Applications for mortgage loans increased 0.6% on a seasonally adjusted basis last week from one week earlier, according to the Mortgage Bankers Associations weekly report on its Market Composite Index, MBA said Wednesday.

On an unadjusted basis, the Index increased 25.2% compared with the previous week, which included Labor Day. The seasonally adjusted Purchase Index decreased 4.7%; unadjusted it was up 17.1%. The Refinance Index increased 2.2% from the previous week.

The four week moving average for the seasonally adjusted Market Index remained down 3.15%; for the seasonally adjusted Purchase Index it was down 0.54% and was down 3.91% for the Refinance Index.

The refinance share increased to 78.3% of total applications from 76.8 percent the previous week. The adjustable-rate mortgage (ARM) share of activity decreased to 6.7% from 7.3%.

During the month of August, the investor share of applications for home purchase, a new metric in the survey, was 5.7%, up from 5.5% in July, led by an increase in the Pacific region. The share of purchase mortgages for second homes increased to 6.0% in August from 5.9% in July.

The average rate for 30-year fixed-rate conforming mortgages ($417,500 orless) remained unchanged at 4.29%, with points increasing to 0.41 from 0.38.The rate for 30-year fixed-rate mortgages with jumbo loan balances (above $417,500), also a new metric in the survey, decreased to 4.55% from 4.57% with points increasing to 0.46 from 0.42. The rate for 30-year fixed-rate mortgages backed by the FHA decreased to 4.07% from 4.08%, with points increasing to 0.51 from 0.48. The rate for 15-year fixed-rate mortgages decreased to 3.46% from 3.52%, with points increasing to 0.45 from 0.38. The rate for 5/1 ARMs decreased to 2.96% from 2.99%, with points increasing to 0.49 from 0.46 (including the origination fee) for 80 percent loan-to-value (LTV) ratio loans.

Beginning with this survey, results will be based on an enhanced sample which captures more than 75% of all retail and consumer direct channel mortgage applications, compared to 50% previously.